This invention relates to a cut-off machine of the type especially suitable for use in association with fabrication mills producing a continuously emanating elongated workpiece of constant cross section, such as welded tubing. More particularly, the invention concerns cut-off machines of the type in which a cut-off die set is caused to be operated during traversing movement with the workpiece as it emanates from the tubing mill.
A variety of cut-off machines have been used in the past to rapidly and successively sever materials emanating from a mill at a constant rate. Examples of such cut-off machines are shown in U.S. Pat. Nos. 3,288,012, 3,288,011, 4,228,706 and 4,354,409.
Cut-off machines of the above-mentioned type include a ram supported on the machine frame, for movement through a power stroke. Power is supplied to the ram from a continuously running power source such as an electric motor. The electric motor supplies power to a single flywheel which transfers the power to a power shaft through a clutch and brake assembly. The power shaft may be connected to and supply power directly to the ram or may be connected by a gear train to a second power shaft engaging and driving the ram. As the clutch and brake assembly is selectively actuated the ram is caused to travel through the power stroke causing the cut-off die set to sever a section of the workpiece.
Cut-off machines of this type have proven to be generally satisfactory. However, there are situations, especially where the tubing to be cut is of a relatively large size, where the stresses developed in the drive train of the machine, particularly in the clutch and in the gear teeth, become excessive resulting in excessive maintenance requirements. Excessive maintenance creates down-time not only for the cut-off machine, but for the fabrication mill as well. Increased down time results in lost production and correspondingly lost revenue to the tubemaker. The excessive stresses encountered in the cutting of large sized tubing can be dealt with by substantially increasing the size and strength of the individual components of the drive train but this approach results in an expensive, heavy and cumbersome machine.